WASHINGTON — For the families of four U.S. soldiers killed by insurgents in Afghanistan on Sunday, the partial U.S. government shutdown will take a particularly personal toll.

The Pentagon says it is not allowed to pay these families a "death gratuity," as long as the shutdown continues. The same goes for the family of a Marine who died in Afghanistan on Saturday and any others who die during the budget impasse.

A legal review of a law meant to shield the military from the shutdown determined that, while the Pentagon can promptly pay salaries and other benefits, the $100,000 tax-free payment to families of fallen troops is not covered.

The payment usually comes within a couple of days of a service member's death, helping the family grapple with the immediate financial needs before other federal government benefits become available.

"We have some heart-rending situations," Pentagon Comptroller Robert Hale told reporters in a briefing on the legal review of the "Pay Our Military Act" over the weekend. President Barack Obama signed the law hours before the shutdown started on October 1.

"We've had a number of people die recently and we will be able to pay them, but not until the lapse of appropriation ends."

The Pentagon on Tuesday identified the four U.S. soldiers who were killed on October 6 by an insurgent bomb attack in Zhari district in southern Afghanistan.

They included 25-year-old Jennifer Moreno, a first lieutenant from San Diego, and 24-year-old Sergeant Patrick Hawkins of Carlisle, Pennsylvania.

The 19-year-old Marine who died on Saturday, Lance Corporal Jeremiah Collins, was stationed in Afghanistan's Helmand province. The Pentagon did not disclose his cause of death, saying the incident was under investigation.

The five deaths appear to be the first cases during the shutdown of delayed death gratuity payments for families of U.S. troops serving in the 12-year-old war in Afghanistan.

"It's a disgrace," said Paul Rieckhoff of the Iraq and Afghanistan Veterans of America. "The fact that those families have to deal with this now is just sad and shocking."

A Pentagon spokesman said the death gratuity to families of troops who died in the United States would also be affected by the shutdown. It was not immediately clear how many members of the armed forces have died in the United States since October 1.

It's not just the death gratuity that will be delayed by the shutdown. The Pentagon says it can't immediately pay for families to travel to Dover Air Force Base to witness the return of their loved ones' remains. The Pentagon is also unable to promptly reimburse burial expenses.

One defense official lamented the restrictions, saying: "If the Department was allowed to make death gratuity payments at any point during the shutdown, they would've been paid with great relief."

Advocates for military families said inability to promptly pay death benefits was unfair to loved ones struggling with the deaths of fallen troops.

The Tragedy Assistance Program for Survivors, which assists those grieving the loss of military servicemembers, said it had been receiving calls during the shutdown from families unsure of how their survivor benefits might be affected.

"These benefits were in place when my brother was killed in Iraq in 2007 and it is heart-wrenching to know there are families who will face these challenges on top of the grief and loss and shock of losing a loved one," said Ami Neiberger-Miller, a TAPS spokeswoman.

She added that, as the shutdown continued, some charities are trying to step forward to provide additional support to families, including the Navy-Marine Corps Relief Society.